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| #!/bin/bash | |
| { | |
| # this block disables xtrace for lines from this file, | |
| # while keeping it enabled for user-land reactive code | |
| shopt -s expand_aliases | |
| alias _suppress_xtrace='{ local old_opts="$-"; set $X_OPT; } 2> /dev/null' | |
| alias _restore_xtrace='_restore_opt $old_opts x' | |
| function _restore_opt() { | |
| # restore the given opt to its previous state | |
| local prev_opts="$1" | |
| local opt_to_restore="$2" | |
| if [[ "$prev_opts" == *$opt_to_restore* ]]; then | |
| # opt was previously enabled, to re-enable it | |
| set -$opt_to_restore | |
| else | |
| # opt was previously disabled, to re-disable it | |
| set +$opt_to_restore | |
| fi | |
| } | |
| if [[ "$CHARMS_REACTIVE_TRACE" != 'true' ]]; then | |
| X_OPT="+x" | |
| else | |
| # we are debugging charms.reactive.sh, so enable xtrace internally | |
| X_OPT="-x" | |
| fi | |
| # save options as of import | |
| import_opts="$-" | |
| set +x | |
| } 2> /dev/null # suppress xtrace during import (braces to hide entire block from xtracing) | |
| export PATH=$PATH:$CHARM_DIR/bin | |
| export PYTHONPATH=${PYTHONPATH-}:$CHARM_DIR/lib | |
| if [[ "$0" == "$BASH_SOURCE" ]]; then | |
| echo 'This file contains helpers for developing reactive charms in Bash.' | |
| echo | |
| echo 'Usage:' | |
| echo | |
| echo ' source `which reactive.sh`' | |
| echo | |
| echo ' @when db.ready cache.ready' | |
| echo ' function write_configuration() {' | |
| echo ' db_dsn=$(relation_call --flag db.ready uri)' | |
| echo ' cache_uri=$(relation_call --flag cache.ready uri)' | |
| echo ' chlp render_template db_dsn=$db_dsn cache_uri=$cache_uri' | |
| echo ' }' | |
| echo | |
| echo ' @when_not db.ready cache.ready' | |
| echo ' function report_blocked() {' | |
| echo ' status-set blocked "Waiting for db and/or cache"' | |
| echo ' }' | |
| echo | |
| echo ' reactive_handler_main' | |
| echo | |
| echo 'Helpers available:' | |
| echo | |
| echo ' @hook PATTERN Run decorated function if hook matches' | |
| echo ' @when STATES Run decorated function if states are active' | |
| echo ' @when_not STATES Run decorated function if states not active' | |
| echo ' @when_file_changed FILENAME Run decorated function if file(s) changed' | |
| echo ' @only_once Run decorated function only once' | |
| echo ' set_flag Set / activate a flag' | |
| echo ' clear_flag Remove a flag' | |
| echo ' relation_call Call a method on a relation by flag or relation name' | |
| echo ' all_flags_set Check all flags are active' | |
| echo ' any_flags_set Check any flags are active' | |
| echo ' name_relation_get Get a relation value by relation name (vs ID)' | |
| exit 0 | |
| fi | |
| REACTIVE_ACTION="${1-'--test'}" | |
| REACTIVE_ARGS="${2-}" | |
| declare -A REACTIVE_HANDLERS | |
| declare -A REACTIVE_TESTS | |
| function _get_decorated() { | |
| # find the name of the "decorated" function, given | |
| # that there may be more decorators between us and it | |
| filename=${BASH_SOURCE[2]} | |
| lineno=$((BASH_LINENO[1]+1)) | |
| last_decorator=yes | |
| while sed "${lineno}q;d" $filename | grep -qE "^\s*@"; do | |
| # there are other decorators between us and the function | |
| last_decorator=no | |
| ((lineno++)) | |
| done | |
| func=$(sed "${lineno}q;d" $filename | sed "s/\(function\)\? *\(.*\) *() *{/\2/") | |
| if [[ "$old_opts" == *x* && $last_decorator == yes ]]; then | |
| # pseudo-xtrace function definition when xtrace is active, since | |
| # the @decorator line will be logged anyway (can't suppress it) | |
| >&2 echo "+ function $func() { ... }" | |
| fi | |
| } | |
| function @decorator() { | |
| _suppress_xtrace | |
| _get_decorated | |
| handler_id="$filename:$lineno:$func" | |
| # this "decorates" a function using source-code introspection, registering | |
| # the "decorated" function as a reactive handler with a set of preconditions | |
| # register handler_ids | |
| if [ ! ${REACTIVE_HANDLERS[$func]+_} ]; then | |
| REACTIVE_HANDLERS[$func]="$handler_id" | |
| fi | |
| # register tests | |
| test_name="$1"; shift | |
| test_args=$(printf '"%s" ' "$@") | |
| if [ ! ${REACTIVE_TESTS[$func]+_} ]; then | |
| REACTIVE_TESTS[$func]="'$func' '$handler_id' '$test_name' '$test_args'" | |
| else | |
| REACTIVE_TESTS[$func]="${REACTIVE_TESTS[$func]} '$test_name' '$test_args'" | |
| fi | |
| _restore_xtrace | |
| } | |
| function reactive_handler_main() { | |
| _suppress_xtrace | |
| if [[ "$REACTIVE_ACTION" == "--test" ]]; then | |
| >&2 echo "Running reactive_handler_main for $(basename $0) (test)" | |
| to_invoke=$(charms.reactive test "${REACTIVE_TESTS[@]}") | |
| if [[ -n "$to_invoke" ]]; then | |
| echo $to_invoke | |
| >&2 echo "Will invoke: $to_invoke" | |
| >&2 echo "End reactive_handler_main (test)" | |
| exit 0 | |
| else | |
| >&2 echo "Nothing to invoke" | |
| >&2 echo "End reactive_handler_main (test)" | |
| exit 1 | |
| fi | |
| elif [[ "$REACTIVE_ACTION" == "--invoke" ]]; then | |
| >&2 echo "Running reactive_handler_main for $(basename $0) (invoke)" | |
| invoked=() | |
| for handler in ${REACTIVE_ARGS//,/ }; do | |
| >&2 echo "Invoking bash reactive handler: $handler" | |
| eval "_restore_xtrace; $handler; _suppress_xtrace" | |
| invoked+=("${REACTIVE_HANDLERS[$handler]}") | |
| done | |
| charms.reactive mark_invoked "${invoked[@]}" | |
| >&2 echo "End reactive_handler_main (invoke)" | |
| fi | |
| _restore_xtrace | |
| } | |
| # some helpers and syntactic sugar | |
| alias @hook='@decorator hook' | |
| alias @when='@decorator when' | |
| alias @when_all='@decorator when_all' | |
| alias @when_any='@decorator when_any' | |
| alias @when_not='@decorator when_not' | |
| alias @when_none='@decorator when_none' | |
| alias @when_not_all='@decorator when_not_all' | |
| alias @when_file_changed='@decorator when_file_changed' | |
| alias @only_once='@decorator only_once' | |
| alias set_flag='charms.reactive set_flag' | |
| alias clear_flag='charms.reactive clear_flag' | |
| alias relation_call='charms.reactive relation_call' # Call a method on a named relation | |
| alias all_flags_set='charms.reactive all_flags_set' | |
| alias any_flags_set='charms.reactive any_flags_set' | |
| # DEPRECATED | |
| alias set_state='charms.reactive set_flag' | |
| alias remove_state='charms.reactive clear_flag' | |
| alias all_states='charms.reactive all_flags_set' | |
| alias any_states='charms.reactive any_flags_set' | |
| # DEPRECATED: Use `relation_call --flag <flag> <method>` instead | |
| function state_relation_call() { | |
| _suppress_xtrace | |
| # Call a method on the relation implementation associated with the | |
| # given active state. | |
| flag=$1 | |
| method=$2 | |
| shift; shift | |
| charms.reactive relation_call --flag $flag $method "$@" | |
| _restore_xtrace | |
| } | |
| function name_relation_get() { | |
| _suppress_xtrace | |
| # Helper function around relation-get that accepts a relation name in place | |
| # of a relation ID. | |
| # | |
| # Usage: name_relation_get <relation_name> <unit_name> [<key>] [--format=<format>] | |
| # Note: The --format option must come at the end, if present | |
| relation_name="$1" | |
| unit_name="$2" | |
| key="$3" | |
| if [[ -z "$key" || "$key" == --* ]]; then | |
| key="-" | |
| shift; shift | |
| else | |
| shift; shift; shift | |
| fi | |
| relid="$(charms.reactive relation_id "$relation_name" "$unit_name")" | |
| relation-get -r "$relid" "$key" "$unit_name" "$@" | |
| _restore_xtrace | |
| } | |
| # re-enable xtrace for user code, if it was enabled | |
| _restore_opt $import_opts x |